Organic electroluminescent display device having electrical communication between conducting layer and cathode layer

Abstract

The present invention relates to a light emitting display device, such as an organic electroluminescent device, and a method for manufacturing the same. Particularly, the present invention relates to reducing electrical resistance between the scan lines and the cathode electrode layers so that scan line signals do not degrade significantly degrade. One way to achieve this is to use materials to form the conducting layers of the scan line and the cathode electrode layers such that the conductivities of the conducting layers and the cathode electrode layer are as identical as possible. For example, if a same metal such as aluminum is used to form both the conducting layer and the cathode electrode layer, the resistance would be significantly lowered. In addition, a large contacting area may be provided.

1. An organic electroluminescent display device, comprising:
 a substrate divided into an pixel area and a scan line area disposed at outer side of the pixel area; 
 a plurality of pixels disposed over the substrate in the pixel area; and 
 a plurality of scan lines disposed over the substrate in the scan line area, 
 wherein each pixel comprises an anode electrode layer, a cathode electrode layer and an organic layer disposed between the anode and cathode electrode layers, and the scan line comprises a scan line electrode layer disposed over the substrate, a first sub-electrode layer disposed over the scan line electrode layer and configured to electrically communicate with the scan line, a conducting layer disposed over the first sub-electrode layer and configured to electrically communicate with the first sub-electrode layer, and a second sub-electrode layer disposed over the conducting layer, 
 wherein the cathode electrode layer extends from the pixel area towards the scan line area to be in electrical communication with the conducting layer, and 
 wherein an electrical conductivity of the conducting layer is substantially identical with an electrical conductivity of the cathode electrode layer, 
 wherein the cathode electrode layer is disposed to electrically connect with a side portion of the conducting layer, and 
 wherein the scan line electrode layer, the first sub-electrode layer, the conducting layer, and the second sub-electrode layer are all disposed to expose at least one portion of the substrate over the scan line area, and wherein the cathode electrode layer is disposed to fill in the at least one portion of the substrate over the scan line area. 
 
   
   
     2. The device of  claim 1 , wherein the scan line electrode layer is disposed on the substrate, the first sub-electrode layer is disposed on the scan line electrode layer, the conducting layer is disposed on the first sub-electrode layer, and the second sub-electrode layer is disposed on the conducting layer in the scan line area, and wherein the anode electrode layer is disposed on the substrate, the organic layer is disposed on the anode electrode layer, and the cathode electrode layer is disposed on the organic layer in the pixel area. 
   
   
     3. The device of  claim 1 , wherein the cathode electrode layer and the conducting layer are formed from a same conductive material. 
   
   
     4. The device of  claim 3 , wherein the conductive material is aluminum. 
   
   
     5. The device of  claim 1 , wherein one or both of the first sub-electrode layer and the second electrode layer are formed from molybdenum or from chrome. 
   
   
     6. A structure to provide display signals to a light emitting display having a substrate divided into an pixel area and a scan line area disposed at outer side of the pixel area, comprising:
 a scan line comprising a scan line electrode layer disposed over the substrate in the scan line area, and a conducting layer disposed over the scan line electrode layer in the scan line area and configured to electrically communicate with the scan line electrode layer; 
 a cathode electrode layer disposed over the substrate in the pixel area to extend from the pixel area of the light emitting display; and 
 a organic layer disposed between the cathode electrode layer and an anode electrode layer, 
 wherein the conducting layer and the cathode electrode layer are configured to electrically communicate with each other, and 
 wherein an electrical conductivity of the conducting layer is substantially identical with an electrical conductivity of the cathode electrode layer, and 
 wherein the conducting layer is disposed to extend over the substrate in an area of the substrate not covered by the scan line electrode layer, and wherein the cathode electrode layer is disposed to extend from the pixel area over the substrate so as to be in electrical communication with the conducting layer at the area of the substrate not covered by the scan line electrode layer. 
 
   
   
     7. The structure of  claim 6 , wherein the cathode electrode layer is disposed to be in direct contact with the conducting layer. 
   
   
     8. The structure of  claim 6 , wherein the cathode electrode layer and the conducting layer are formed from a same conductive material. 
   
   
     9. The structure of  claim 8 , wherein the conductive material is aluminum. 
   
   
     10. The structure of  claim 6 , further comprising a sub-electrode layer disposed over the conducting layer, wherein the sub-electrode layer is formed from a material different from the conducting layer. 
   
   
     11. The structure of  claim 10 , wherein the sub-electrode layer is formed from molybdenum or chrome. 
   
   
     12. The structure of  claim 10 , wherein the sub-electrode layer is a second sub-electrode layer, the structure further comprising a first sub-electrode layer disposed in between the scan line electrode layer and the conducting layer, and wherein the first sub-electrode layer is formed from a material different from the conducting layer. 
   
   
     13. The structure of  claim 12 , wherein the first sub-electrode layer is formed from molybdenum or chrome. 
   
   
     14. The structure of  claim 6 , further comprising:
 a first sub-electrode layer disposed in between the scan line electrode layer and the conducting layer; and 
 a second sub-electrode layer disposed over the conducting layer, 
 wherein the first and second sub-electrode layers are formed from materials different from the conducting layer. 
 
   
   
     15. The structure of  claim 6 , wherein the anode electrode layer is disposed over the substrate in the pixel area and crossing the cathode electrode layer, the organic layer is disposed over the anode electrode layer, and the cathode electrode layer is disposed over the organic layer. 
   
   
     16. The structure of  claim 6 , wherein the light emitting display device is an organic luminescent device. 
   
   
     17. The structure of  claim 6 , wherein the scan line electrode layer is disposed on the substrate. 
   
   
     18. The structure of  claim 17 , further comprising:
 a first sub-electrode layer disposed on the scan line electrode layer, wherein the conducting layer is disposed on the first sub-electrode layer; and 
 a second sub-electrode layer disposed on the conducting layer, 
 wherein the first and second sub-electrode layers are formed from materials different from the conducting layer. 
 
   
   
     19. A structure to provide display signals to a light emitting display, comprising:
 a scan line electrode layer disposed over a substrate; 
 a conducting layer disposed over the scan line electrode layer and configured to electrically communicate with the scan line electrode layer; and 
 a cathode electrode layer disposed over the substrate to extend from a pixel area of the light emitting display, 
 wherein the conducting layer and the cathode electrode layer are configured to electrically communicate with each other, 
 wherein an electrical conductivity of the conducting layer is substantially identical with an electrical conductivity of the cathode electrode layer, 
 wherein the conducting layer is disposed to extend over the substrate in an area of the substrate not covered by the scan line electrode layer, and 
 wherein the cathode electrode layer is disposed to extend from the pixel area over the substrate so as to be in electrical communication with the conducting layer at the area of the substrate not covered by the scan line electrode layer.